Drying apparatus



Sept. 13, 1938. L. E. OLCOTT ET AL DRYING APPARATUS 4 Sheets-Sheet l Filed April 15, 1932 I ll rio

l I I I l l I 1I I l I r I I I r I INVENToRs Laurence E. OICo CAQuelond C. Super Kerl W'. Grosche William T Runl ATToRNEY Sept. 13, 1938. L. E. oLcoTT ET AL 2,130,246

DRYING APPARATUS Filed April l5, 1932 4 Sheets-Sheet 2 m m s m mw m m 5 5 l Omumm A l QR MO n. du? m A wwnm ymwwwq A... i j l I l I l m: AWN VII! I,

Sept. 13, 1938. E. oLcoTT ET A1.

DRYING APPARATUS Filed April l5, 1932 4 Sheets-Sheet 3 nrw 5 u mkwea m E o A o@ @m MMG?A dwm nl www. LCKW ---.l 1 l I l l l Sept. 13, 1938. E QLCOTT ET AL 2,130,246

DRYING APPARATUS Filed April l5, 1932 4 Sheets-Sheet 4 INVENToRs 38 Laurence E. lco

- Cleveland C. oper '56 Karl W. Gasohe BY William T. Rurml ATTORN EY5 Patented Sept. 13, 1938 UNITED ASTATES PATENT OFFICE Darme. APPARATUS Laurence E. Olcott, Akron, Cleveland C. Soper, Kent, Karl W. Gasche, Stow, and William T. Runals, Akron, Ohio, assignors, by mesne assignments, to The Firestone Steel Products Company, Akron, Ohio, a corporation of Ohio Application` April 15, 1932, Serial No. 605,484 2 Claims. (Cl. 34-12) This invention relates to drying methods and plates is about degrees higher than that used apparatus.. and more especially it relates to prowith negative plates. The humidity in the zone cedure and apparatus for drying storage battery is practically 100 per cent, that is, there is complates after the latter have been coated with plete saturation of the atmosphere. In this zone 5 litharge (PbO) or red lead (Pb304) in the manuthe humid atmosphere keeps the outside of the facture thereof. work in wet condition, so that the drying thereof The chief objects of the invention are to prois initiated from the interior of the viscous coatduce improved storagebattery plates; to produce ing. storage battery plates having an uncracked or The passage of the work through the drying uncrazed surface coating; to effect economy in zone requires about 44 per cent of the total time. the manufacture of battery plates; and to reduce The temperature in this zone is maintained bethe time required for drying the coated plates. `tween 250 and 280 degrees, although a tempera- `Other objects'will be manifest. Y ture of 300 degrees may be used if desired. The Of the accompanying drawings: heat in this zone is dry heat, and the temperature Figure 1 is a front elevation of apparatus ememployed depends upon conditions of drying. bodying and adapted to carry out the invention, The major part of the drying of the work occurs in its preferred form; in the drying zone, the drying progressing from Figure 2 isa section on the line 2-2 of Figthe interior to the surface of the coating on the 111'@ 1; plates. 20 Figure 3 is a section on the line 3 3 of Flg- Both the humidity zone and the drying zone. ure l; are gas fired, arid the products of combustion go Figure 4 is a section on the line 4 4 of Figdirectly into the air which circulates within said Ure 1; zones. Suiilcient amount of gas is burned, and Y cooled if necessary, so that the air going into these zones has a CO2 content of from 2 to 4 per cent determined by the Orsat method. The function of the CO2 in the drying atmosphere is to Figure 51s a side elevation of the apparatus as viewed from the left of Figure 1, parts being broken away for clearness of illustrating;

Figure 6 is a section on the line 6--6 ,of Figure 1, and f combine with the litharge or red lead on the bat- Figure 7 is a section on the line 1-1 of Figtery plates to formahard protective surface layer 30 ure 6- of lead carbonate (PbCOa) thereon. This layer is hard and coherent, and because the coating is dried from the interior outwardly, is uncracked or uncrazed. Thus it prevents aking off of the coating during subsequent service use.

Referring now to the drawings wherein is illustrated the apparatus employed for the practice of the foregoing method, there is provided a relatively large closed oven III at one end of whicr is a somewhat narrower downward extension Il. Interiorly of the extension II isra transverse ver- In the drying of storage battery plates by our improved method, the wet plates, of which the positive plates are coated with a plastic mass of red oxide of lead and the negative plates are coated with a similar mass of litharge, are passed successively and progressively through three regions or zones of different conditions of temperature and humidity, namely, a preheating zone, a humidity zone, and a drying zone. The passage of the work through the pre-heating zone requires approximately 12 per cent of the time required for complete drying. In this' zone the temperature varies from room temperature to 180 F. maximum, or whatever temperature is being maintained in the humidity zone. It is likely that there is increasing humidity in the pre-heating zone towardthe region thereof of highest temperature. In this zone the work is gradually warmed without causing any drying of the coating on the plates.

Passage of the work through the humidity zone requires about 44 per cent of the total time. The temperature in this zone may be as high as 180 dry bulb with the wet bulb 4 degrees lower. Preferably the temperature used with positive stantially in half, and extends well up into the oven. Within the oven I0 is an enclosed chamber of which the aforesaid partition I2 is one end wall thereof, horizontal partition I3 is the top,` vertical partition I4 is the other end wall, and partitions Illa, Illb are the front and rear side walls thereof, said from the side walls of the oven as is most clearly shown in Figures 5 and 6. Within said chamber are partitions I5, I6 that extend from the bottom thereof to points adjacent but spaced from the chamber-top I3. A That portion of the oven that is betweenpartitions I2. I5 is the pre-heating'zone and is desigtical partition I2 that divides the extension subside walls being spaced nated A. The interior of the enclosed chamber between partitions I5, I6 is the humidity zone and is designated B. That portion of the oven above partition |3 is the drying zone and is designated C. 'Ihere is a somewhat indeterminate region between zones B and C between partition I6 and the adjacent end wall of the oven.

The space between partition I2 and the adjacent end wall of the oven is not heated, and in here the work cools somewhat before it is delivered from the oven.

Extending through the several zones of the oven is an endless conveyor |8 comprising parallel sprocket chains 9, 28 `(Figures 5 and 6) that carry between them a multiplicity of pivotallyl suspended supports or trays 2|, 2|. Work supported upon said trays is designated 22. The chains I9, 28 are trained about a series of suitably mounted sprockets 23, 23, and a pair of sprockets 24 that are mounted upon a shaft 25 that extends through the wall of the oven and is provided exteriorly of the latter with. a sprocket 26 that is driven by a chain 21 from a suitable source of power (not shown). The conveyor is driven in the direction indicated by the arrow in Figure 7, and is disposed in loops within the oven zones B and C so that the work remains in these zones for the required interval of time.

In the lower part of the oven extension II is' a work-receiving orifice 38 opening into the preheating zone A, and positioned adjacent said orifice, exteriorly of the oven, is a gravity conveyor 3| for the work, said conveyor preferably being provided with suitable release mechanism 32 that is successively actuated by trays 2 I whereby automatic loading of the latter is effected.

In the opposite side of the oven extension I I is a work-delivery orifice 33 opening into the unheated, cooling zone of the oven, and a gravity conveyor 34 extends through said orifice and into the path of conveyor I8 in such a manner as automatically to remove the work from the trays 2| of the conveyor, and to deliver the work to the place desired.

At the bottom of the ovenextension |`I is a well 36 in which is a cooling fiuid 31 such as water.

An inlet pipe 38 and an outlet pipe 39 are provided for said well, the outlet pipe serving to keep the fluid at a determined level. The arrangement is such that empty trays 2| of the conveyor I8 pass through the cooling fluid 31 just before they receive work from the gravity conveyor 3|, so that the cooled trays transmit no heat to the work.

The pre-heat zone A is arranged to draw some air from the top of' the humidity zone B over the top of partition I 5. Also there is provided a motor driven fan 40 that has an intake duct 4| extending interiorly of the oven to an opening 42 into the humidity zone B, said duct having a branch 43 (Figures 5 and 6) extending across the end of the oven` and opening into the lower part of the coo1- ing zone, between the partition I2 and the end of the oven. 'Ihe fan 40 hasa delivery duct 44 disposed between the oven wall and wall Illa, and opening into the pre-heat zone at one or more points 45, 45 depending upon the desired control, which may be regulated from the outside. Fresh air enters the pre-heat zone through orifice 30. The arrangement is such that the atmosphere in the pre-heat zone is progressively warmer and ymore humid as it approaches the entrance to the humidity zone.

Mounted upon the front side of the oven I0 exteriorly thereof is a humidifier 48 at one end of which is a motor driven fan 49 having an exhaust duct 50 that is disposed between the walls I8 and Ilia and has a discharge orice 5| in thelower part of the humidity zone B. 'I'he humidifier has an inlet duct 52 having two inlet ports 53, 54 respectively opening into the humidifier and into the passage betweenl the humidity zone B and drying zone C. The humidifier 48 recirculates the air within the humidity zone.

Itis of standard construction and includes steam coils (not shown) for heating the air passing therethrough, and a steam jet (not shown) for humidifying the air. Near the point where the inlet duct 52 enters the humidifier is a gas burner 55 that is so arranged that the products of combustion containing CO2 go into the recirculating air stream.

Also mounted upon the outside wall of the oven, beside the humidifier, is a heating unit 58 of the usual type including heating coils (not shown). At one end the heating unit 58 is connected to an inlet duct 59 (Figure 6) that has an inlet port in the wall of oven I0 and takes in air from between the walls I0, |0a. At the opposite end of the heater 58 is a motor driven fan 60 that has a fresh air intake 6|, and an exhaust duct 62 that extends through the adjacent oven wall and across the top of humidity zone B. The duct 62 has branch ducts 63, 63 extending laterally between the walls I 0, Illa and I 0, |0b, each of said branch ducts being provided with a plurality of outlet ports 64, 64. Connected to the heating unit 58 is a gas burner 65 similar to that shown at 55. The heating unit 58 supplies heat and gas to the drying zone C.

The drying zone C has a vent 61 to the exterior of the oven, said vent having a damper therein. A similar vent 68 is provided for humidity zone B. Below the oven I0 is mounted a motor driven suction fan 69 having an inlet duct 18 (Figure 5) communicating with the lower region of the preheating zone A, said fan having a discharge duct 1| extending to the roof of the building that houses the oven. 'I'he vents 61, 68 and exhaust duct 1| are used for purging the oven of all gas before starting operation. They may also be used to control the amount of moisture recirculated in the system.

The air in the respective zones of the oven is kept constantly in circulation, so that uniformity of temperature, humidity, and gas content is maintained. The method and apparatus conserve time in the manufacture of storage battery plates, improve working conditions, and achieve the other objects set out in the foregoing statement of objects.

Modification may be resorted to without departing from the spirit of the invention, or the scope of the appended claims which are not limited wholly to the specific construction shown or exact procedure described.

What is claimed is:

1. In drying apparatus the combination of an oven comprising a pre-heating compartment, a humidifying compartment and a drying compartment, an endless conveyor traversing said compartments, a humidifier, means for recirculating air through the humidifier and through the humidifying compartment, a heater, means for recirculating dry air through the heater and through the drying compartment, and respective gas burners so connected to the humidifier and to the heater as to inject the products of combustion of said gas burners into the air streams passing through said humidifier and heater.

2. Apparatusvfor drying storage battery plates containing a thick viscous paste, said apparatus comprising an endless conveyor and a series of compartments traversed by said conveyor, the latter being adapted to carry battery plates placed thereon successively through saidcompartments, said compartments comprising a preheating compartment, means 'for heating the atmosphere in said compartment for heating said plates and the paste thereon, a humid atmosphere compart ment, means for humidifying the atmosphere in said compartment for preventing the surface of said paste from drying before the interior thereof, a drying compartment, means forremoving humidity from the atmosphere in said drying compartment for removing the moisture from said lpaste, means for continuously driving said conveyor for progressively presenting said plates to said pre-heating compartment, said humidifying compartment, and said drying compartment,

means for directing the conveyor through a path in the preheating compartment for a distance approximately 12% of the total distance of travel of said battery plates in said apparatus, in the hurnidifying compartmentV approximately 44% of the total distance of travel of said battery plates and in the drying compartment approximatew 44% of the total distance of travel of said battery plates, whereby plates carried by the conveyor Will be treated in the respective compartments for periods correspondingly proportional to the total time of treatment, as the conveyor moves through the compartments at a substantially uniform speed.

LAURENCE E. OLCOTT. CLEVELAND C. SOPER. KARL W. GASCHE. WILLIAM T. RUNALS. 

